Effects of antibodies to nerve growth factor on sprouting following spinal cord hemisection in the rat

Dorsal root unmyelinated axons in 30-day-old rats in which the spinal cord has been hemisected at birth are more numerous on the operated side in animals that receive preimmune serum daily from hemisection to sacrifice. This is interpreted as indicating that sprouting of sensory axons occurred on the operated side. In animals with hemisected cords treated daily with antibodies to nerve growth factor (anti-NGF), the same numbers of unmyelinated axons are found in the roots on the operated side, but there are even more unmyelanated axons on the unoperated side. Our interpretation is that anti-NGF results in sensory axon sprouting with more sprouts on the unoperated side. Thus removal of NGF in cord hemisected newborn rats has an effect on sensory axon numbers.